The present invention relates to an aircraft of the airship type, which has a bottom face of flat shape and is of a general shape designed to produce, under the effect of relative wind, an overall downward resultant force when close to the ground. According to the invention, this aircraft further comprises a device for anchoring to the ground, fixed or maneuverable from said aircraft, which is located in the front portion of said aircraft and extends downwards, in particular a rigid fixing punch, comprising a part that is expandable by a ramp bearing against a nut displaced in translation.
The invention also relates to a method of landing using such an aircraft. This method comprises, under the effect of the downward force with compensation by maintaining a nose-up attitude, a descending flight until there is contact of a rear portion of the aircraft; followed by a decrease in nose lift until the anchoring device makes contact with the ground, in particular with the driving of a punch into the ground. Preferably, the method further comprises mooring, in particular by means of an expandable punch, while the aircraft is pinned to the ground under the effect of the downward force.
Among aircraft making use of the lift of a gas that is lighter than air, those equipped with propulsion are often called “airships”.
Airships were used on a wide scale for several decades, for example during the first half of the twentieth century. Many projects are seeing the light of day again after several decades, for commercial uses such as for example advertising displays or the transportation of heavy loads, to take advantage of the many possibilities offered by this technology.
For example, this “lighter-than-air” technology allows slow or stationary flight, of long duration, without noise and without consuming energy for lift. It can use technology that is less complex and less expensive than in “heavier-than-air” aeronautics, constituted by aeroplanes and helicopters or hybrids thereof. This technology can also be used with little risk of mechanical failure and with a low degree of criticality in the case of accidents, since helium replaced hydrogen as the lifting gas.
Nevertheless, the piloting and maneuvering of an airship still pose a certain number of difficulties, some of which are connected with the large overall dimensions of the body that encloses the lifting gas, and therefore with the wind drag that its envelope represents.
Landing in particular is a difficult manoeuvre, which requires both good piloting skills and considerable assistance on the ground, in terms of equipment or in terms of personnel. In fact, when approaching the ground in non-zero wind conditions, an airship is subjected to irregular forces that cause considerable, unpredictable vertical lurching. These forces make a risk-free approach all the way to the ground difficult or impossible at wind speeds above the order of 20 km/h for a hot-air airship, and about 40 km/h for a helium airship in the real configurations that are currently used the most.
That is why it is always necessary to have the benefit of assistance on the ground. Now, as before, this assistance is most often provided by a team of several persons who grasp ropes coming down from the airship from a certain height, and then use them for bringing it to the ground manually or for mooring it to a mast by a winch. For example, a recent model of helium airship for twelve persons requires from three to eight persons and/or a mooring mast positioned on a lorry or anchored in concrete foundations.
Solutions have been proposed that consist of providing automatic attaching means on the ground, as in document EP 2 154 070 or document FR 2 581 962. Sometimes these solutions are still complex, and do not allow unassisted landing in a place that has not been prepared.
One aim of the invention is to remedy the drawbacks of the prior art, and in particular to facilitate the landing of an airship, for example in a place that has not been prepared and/or without assistance on the ground.